Learning objective: Designing K-12 schools: HVAC systems

In K-12 schools, technological advancements, code requirements, and other demands placed on engineers are consistently increasing, while limitations like budget restraints remain a challenge. HVAC systems, air quality, and acoustics are discussed here.



  • David Ellis, PE, CEM, LEED AP Senior Vice President of Engineering Allen & Shariff Engineering LLC Columbia, Md.
  • Nestor Ortiz Senior Construction Engineer, Project Officer Parsons Brinckerhoff Long Island City, N.Y.
  • John C. Palasz, PE, HFDP Mechanical Engineer Primera Engineers Ltd. Chicago


Primera Engineers was engaged to renovate the boiler at Chicago’s Carl Schurz High School, a historic landmark. The team replaced steam boilers with 500-hp, low-pressure steam boilers, added steam-to-water heat exchangers, two 365-ton centrifugal chillers, cooling towers, and other components. The project also included a new building automation system. Courtesy: Primera Engineers Ltd.CSE: What unique HVAC requirements do K-12 school structures have that you wouldn't encounter on other structures?

Ellis: Acoustical standards stand out as the differentiator, as system-based noise has detrimental impacts on learning, much more so than the same levels have on office production or other similar activities. Maintenance staff may not have the training to adequately support complex systems, and as such require system operation and maintenance to be as straightforward as possible; with complex systems, such as related to renewable energy systems, it may be outsourced for ongoing support.

CSE: What changes in fans, variable frequency drives, and other related equipment have you experienced?

Ellis: The biggest change in the design approach has been the introduction of de-coupling of ventilation from conditioning by the use of DOAS, and the application of VRF systems. DOAS allows for substantial energy savings in the avoidance of conditioning unnecessary ventilation air, and VRF allows for low-energy transport of heat during periods of concurrent heating and cooling. Of course, improvements in design and cost of variable frequency drives (VFDs) allows for more opportunities for implementing the energy-saving advantages associated with variable flow, both air and water, and development of inexpensive pressure independent constant air regulators allows for the mixing of constant and variable flow ventilation on the same variable air volume (VAV) DOAS, which allows for ventilation savings with highly variable occupancy classrooms with fixed makeup spaces, such as labs.

Palasz: Over the past few years, I have experienced a change in the trend of using a roof-mounted return fan in an insulated housing (similar to a rooftop unit) to wrapping a mixed flow fan. This results in a lighter and more efficient design, which helps to decrease initial costs by reducing the structural reinforcement requirements. It also helps to improve the return on investment with a very efficient fan (up to 85% efficient).In regard to VFDs, they have become less expensive and more widely used to provide system flexibility and soft-start capability in addition to diagnostic alarms.

CSE: Do you find it more challenging to retrofit HVAC systems on older buildings than installing on new?

Palasz: Yes, I find it more challenging to retrofit HVAC systems because the older buildings often have space limitations, structural limitations, and additional expenses due to building materials requiring abatement. This often requires a great deal of time and effort to survey the existing system as well as a great deal of documentation.Additionally, system deficiencies are often discovered during the site survey that can easily lead to an increase in scope. A diligent project manager can help define and track scope expectations clearly.

No comments
Consulting-Specifying Engineer's Product of the Year (POY) contest is the premier award for new products in the HVAC, fire, electrical, and...
Consulting-Specifying Engineer magazine is dedicated to encouraging and recognizing the most talented young individuals...
The MEP Giants program lists the top mechanical, electrical, plumbing, and fire protection engineering firms in the United States.
Commissioning lighting control systems; 2016 Commissioning Giants; Design high-efficiency hot water systems for hospitals; Evaluating condensation and condensate
Solving HVAC challenges; Thermal comfort criteria; Liquid-immersion cooling; Specifying VRF systems; 2016 Product of the Year winners
MEP Giants; MEP Annual Report; Mergers and acquisitions; Passive, active fire protection; LED retrofits; HVAC energy efficiency
Driving motor efficiency; Preventing Arc Flash in mission critical facilities; Integrating alternative power and existing electrical systems
Putting COPS into context; Designing medium-voltage electrical systems; Planning and designing resilient, efficient data centers; The nine steps of designing generator fuel systems
Designing generator systems; Using online commissioning tools; Selective coordination best practices
As brand protection manager for Eaton’s Electrical Sector, Tom Grace oversees counterfeit awareness...
Amara Rozgus is chief editor and content manager of Consulting-Specifier Engineer magazine.
IEEE power industry experts bring their combined experience in the electrical power industry...
Michael Heinsdorf, P.E., LEED AP, CDT is an Engineering Specification Writer at ARCOM MasterSpec.
click me